Adsorption of Hydrogen in Microporous Carbon Adsorbents of Different Origin

Фомкин, А. А.; Прибылов, А. А.; Murdmaa, K. O.; Пулин, А. Л.; Школин, А. В.; Меньщиков, И. Е.; Zhedulov, S. A.

doi:10.1134/s2070205119030134

Cited by 13 publications

(3 citation statements)

References 27 publications

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“…Indeed, according to Schlapbach and Zuttel [78], the maximum hydrogen adsorption capacity on a porous solid is 1.3 × 10 -5 mol m -2 , which leads to a maximum uptake of 34 mol kg -1 (i.e., 6.8 wt.%) for a graphene sheet whose specific surface area is 2630 m 2 g -1 [63]. Using the A BET obtained from the textural characterisation of the two ACs studied, we calculated the hypothetical maximum hydrogen storage for both MSC30 and MSP20X, i.e., 42.96 mol kg -1 and 30.72 mol kg -1 , respectively, which are considerably lower than the values obtained from the fit of the data (i.e., 72.46 and 47.38 mol kg -1 , respectively). In addition, the definition of V a still remains ambiguous.…”

Section: Application Of the Modified Dubinin-astakhov (Mda) Equationmentioning

confidence: 99%

“…The heat of adsorption is generally evaluated by using the sorption isosteric method [39], which consists in applying the Clausius-Clapeyron equation to the adsorption isotherms calculated over a wide range of temperature and pressures. The latter method reliably determines the isosteric heat of adsorption [40], which ranges from 3 to 7.5 kJ mol -1 [41] for hydrogen adsorption on the Metal Organic Framework (MOF) MIL-101 and on different microporous carbon adsorbents [42]. The smallest pores contribute the most to the average heat of adsorption and are the first to be filled [43], and the heat of adsorption decreases with the surface coverage [44,45].…”

Section: Introductionmentioning

confidence: 99%

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Application of the modified Dubinin-Astakhov equation for a better understanding of high-pressure hydrogen adsorption on activated carbons

Sdanghi

Schaefer

Maranzana

et al. 2020

International Journal of Hydrogen Energy

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Hydrogen storage in activated carbons (ACs) has proven to be a realistic alternative to compression and liquefaction. Adsorption capacities up to 5.8 wt.% have indeed been obtained. The amount of adsorbed hydrogen depends on the textural properties of ACs, such as specific surface area and total pore volume. The modified Dubinin-Astakhov (MDA) equation proved to be a good analytical tool for describing hydrogen adsorption in a wide range of pressures and temperatures and for several adsorbents. The parameters of this model have been found to be somehow related to the textural properties of the adsorbent. Thus, we applied this model to understand better hydrogen adsorption on ACs over a wide range of pressures in relation to the textural properties of the ACs. We applied the MDA equation to evaluate also the isosteric heat of hydrogen adsorption, which was found to be in the range of 5 to 9 kJ mol-1. We compared the results obtained by applying the MDA equation with those obtained by both the sorption isosteric method and the Sips equation. This allowed finding the temperature dependence of the isosteric heat of adsorption, as well as its variation with respect to the textural properties of the ACs.

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Section: Application Of the Modified Dubinin-astakhov (Mda) Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of the modified Dubinin-Astakhov equation for a better understanding of high-pressure hydrogen adsorption on activated carbons

Sdanghi

Schaefer

Maranzana

et al. 2020

International Journal of Hydrogen Energy

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“…However, a number of works [12,[21][22][23][24][25][26][27][28][29][30][31][32] shows that the DRA equation can be used to quantitatively describe experimental isotherms also at temperatures above critical by more than 100-150 K on active microporous carbons, zeolites, silica gels, and molecular sieves. In particular, the DRA equation can be used to describe the adsorption of CH4, N2, H2 on Zeo-5A@MOF-74-1 zeolite at temperature T = 298 K and pressure P = 0-22 atm [12]; H2 on active carbons [23,24]; Ar on zeolite 13X [32]; CH4 on zeolites 13X, CaLSX, KLSX, LiLSX at T = 298-343 К and P = 0-1 atm [31]; CH4, N2 on zeolites Cu-BTC and MaxSorb at T = 298-303 К and P = 0-40 atm [30]; CO on zeolite 13X at T = 293-343 К and P = 0-1 atm [27]. Works [22,25] propose to replace the saturation pressure with standard pressures.…”

Section: Introductionmentioning

confidence: 99%

On the Issue of Using the Dubinin–radushkevich–astakhov Equation in Calculating Isotherms of H2, Co2, Co in the Pressureswing Adsorption Process for Hydrogenrecovery on Block Zeolites 13x

2022

Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.

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The calculation of adsorption isotherms of synthesis gas components in the process of pres-sure swing adsorption (PSA) for hydrogen extractionon zeolite adsorbents is traditionally carried out using the Langmuir equation or equations derived from it. Its disadvantage consists in the necessity to obtain experimental adsorption isotherms for each gas in the gas mixture on the used adsorbent. This approach is expensive, especially in the case of multicomponent mixtures, such as synthesis gas. The paper demonstrates the prospects of an alternative method for calculating ad-sorption isotherms of H2, CO2, CO gases in the PSA process for hydrogen extracionfrom synthesis gas on block zeolites 13X using the Dubinin–Radushkevich–Astakhov (DRA) equation. Using zeo-lites 13X made by three samples, experimental adsorption isotherms of H2, CO2, CO at temperatures of 293 and 323 K, and adsorption isotherms of N2ata boiling point of 77.35 K were obtained. Using experimental isotherms, the problems of parametric identification were solved, and the parameters of the DRA equation for H2, CO2, CO gases on block zeolites 13X were determined. It has been found that the calculation of adsorption isotherms of H2, CO2, CO gases on zeolites 13X, the char-acteristics of which fall within the ranges of the limiting adsorption volume 0.258–0.296 cm3/g and the characteristic adsorption energy 10279–13395 J/mol, respectively, can be correctly carried out using the DRA equation in the temperature range of 293–323 K and the pressure range of 0–30 atm.In this case, the maximum value of the mismatch between the experimental gas isotherms and those calculated by the DRA equation is 14.69% for H2; the minimum value is 1.81% for CO2. Certain affinity coefficients make it possible to calculate the adsorption isotherms of H2, CO2, CO gases in the obtained ranges of the limiting adsorption volume and characteristic adsorption energy using only one isotherm of the standard gas (N2) on the zeolite 13X used. The versatility of the DRA equation can be used to calculate the adsorption isotherms of various gases, mixtures, and adsor-bents in cyclic adsorption processes.

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